The sleep in which there is a luminous silence or else the sleep in which there is Ananda in the cells, these are obviously the best states. The other hours, those of which you are unconscious, may be spells of a deep slumber in which you have got of the physical into the mental, vital or other planes. You say you were unconscious, but it may simply be that you do not remember what happened; for in coming back there is a sort of turning over of the consciousness, a transition or reversal, in which everything experienced in sleep except perhaps the last happening of all or else one that was very impressive, recedes from the physical consciousness and all becomes as if a blank. There is another blank state, a state of inertia, not only blank, but heavy and unremembering; but that is when one goes deeply and grossly into the subconscient; this subterranean plunge is very undesirable, obscuring, lowering, often fatiguing rather than restful, the reverse of the luminous silence.